MST-Department of Physics

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Computation of electronic properties of amorphous silicon (a-si) in the random phase model
(2012-05-02) Wambua, Yifta M.; Okumu, John; Dod, T. S.
The electrical conductivity and the Hall effect in amorphous silicon have been studied as a function of the Fermienergy. This was done by direct computer simulation of these quantities for a realistic model structure of amorphous silicon containing 1728 atoms. This structure was generated by computer simulation using molecular dynamics and the equation of motion method. It has been shown that the random phase model (R.P.M) in tight binding approximation (T.B.A) for the electronic wave functions give a very reasonable agreement with recent computations of the electrical conductivity. The results obtained were also in good agreement with experimental values and more importantly, we have succeeded in verifying the anomalous change in sign of the Hall effect as the conduction band in accordance with the experimental observations of Le Comber, Jones, and Spear in 1977. The experimental values of Hall Mobility obtained by LeComber et al range from 1.1 x 10-5 m2v-1s-1 to 2.8 x 10-5 m2 v-1s-1 and hence the computed peak of 2.6 x 10-5 m2v-1s-1 given about 90% agreement.